It's like saying my grandfather was Indian, so I'm Indian... even though the other parts are Caucasian. All production reds originally come from heritage reds, but that definitely doesn't make them heritage by any stretch of the imagination...
If the breeder introduced a heritage bird or two into the flock, there may be a few offspring that will show some similarities to heritage birds, but this most likely won't get passed down into the next generation. It's virtually impossible to breed out the production gene, so it's best to either go all out heritage... or not at all. While you make change the appearance of the productions to make them look "nicer", it's probably not going to end with satisfactory results. Either color will be messed up, egg production impacted, or both. Mating a thoroughbred to a mutt does't give satisfactory results with other animals, and chickens are no different. Just my opinion...